At present, mainstream displays in the market include thin film transistor-liquid crystal display (TFT-LCD) devices and active matrix organic light emitting diode (AMOLED) display devices, where: the TFT-LCD devices control a polarization direction of light emitted from a back light source through a liquid crystal layer, and obtain desired colors and gray scales through filtering by a color filter; the AMOLED display technology does not need any back light source, and transforms power into light directly. However, when the above two display devices display images, at least three sub-pixels of RGB are needed for each pixel, and the setting of the sub-pixels limits resolution improvement of the display devices.